Saturday, July 21, 2012

We All Spend Time As A Shadow

I leave my apartment and hop in the car, already feeling a little drowsy. It's 10:30 pm, and I'm heading to work. In order to satisfy a requirement for an internship, I scheduled two ED shadowing shifts back to back, starting at 11pm and going till 7am. I took two shifts previously from 6pm to 2am, but this was different. Going to work in the middle of the night feels unnatural, though the commute is pretty good. I arrive at the hospital, carrying my coffee-filled thermos (essential), ready for the night shift.

So, you want to be a doctor. Fantastic (although if I had a nickel for every time I heard that, I wouldn't be taking out so many loans for med school). What does a doctor do? If you answered "Helps people" you are probably a freshman with good intentions but much naïveté. If you chose "Paperwork" or "Sitting at a computer" you probably have a little more experience. If you said "Inflict pain and interrupt frequently" you are probably a patient. Most people have a general idea of what physicians do, but they lack the important day-to-day details. Medicine is fairly romanticized thanks in large part to shows like ER, House, or Grey's Anatomy, and the many that came before it. Watching people put in orders, review charts, wait for labs, or conduct rounds does not make for very interesting TV (to the general public at least). Thus we arrive at our stereotypical freshman pre-med, gunning for med school without any conception of what physicians actually do. This is where shadowing comes in.

The ED is arranged like a giant horseshoe, the interior being the nurses' and physician's stations and the exterior being the patient rooms. I set my coffee down and put my snack in the mini-fridge (god help you if you fail to bring snacks). I greet Dr. S. and we begin the night. Dr. S. is very mild mannered and speaks calmly (ER docs tend to come from both ends of the spectrum, calm and manic). It is a typical night at the ER; abdominal pain is coming at us from every direction and shows no sign of letting up. Not too far into the shift, an elderly woman arrives by EMS. She was unconscious and had some dried blood on her head, suspicious for a fall. She was weakly responsive to pain, but no spontaneous movement or sounds. She got the usual 'ER Special' consisting of IVs, blood tests, and cardiac monitoring. She would almost certainly be admitted. Neurology would be consulted as soon as possible. Several hours later, her daughter came running out of the room, shouting for help; the patient was having a seizure. After a tense minute or two of not being able to locate any nurses or Dr. S. (he is the only physician on at this point), we stream into the room to assess the situation. The patient has stopped seizing at the moment, but is now not breathing. Her heart rate plummets. Quickly, a nurse starts to bag her, and Dr. S. makes the decision to intubate. Respiratory is paged, and a nurse prepares anti-convulsants. Finally, she's stabilized, and we all go back to work. No rest for the weary.


Shadowing is exactly as it sounds: the student follows the physician like a shadow, in order to observe. However, unlike a shadow, you will constantly be in the way, and you can/might be allowed to ask questions. Medical students are expected to ask questions, even if they end up being forced to answer their very own questions and ultimately being chastised for not knowing the answer (doesn't seem fair does it). It is extremely useful though, because you gain firsthand knowledge of how a typical day/shift goes. For example, I was shadowing an ER doc, and for the first 2-3 hours, we didn't see one patient. Labs were backed up and beds were full, so we just sat on our asses until it cleared out a bit. You do get to see procedures and patients (especially in surgery), but the little things are actually the most important. Adcoms want to see that you know what you're in for; the fairy-tale can be your motivation, but you better be prepared for the reality.

Around 5am or so, Dr. S. are seeing a patient about back pain when the intercom clicks on. "All help to triage stat!" the nurse shouts (first time I heard stat used in a serious context). Dr. S. is not phased, and continues to interview the patient. Seconds later, "Physician to triage!" Dr. S. sighs, apologizing to the patient, and we head down the hall to the waiting room (slowly I might add). Before we get there, two beds complete with patients come flying around the corner, pushed by a couple personnel. Both patients were stabbed at a party and had just walked in the front door. Minutes later, a third patient comes in and is wheeled back to an empty bed. The ED goes into lock-down, police are called, vitals and IVs are started, and ambulances are called to transfer the patients (the hospital is not a trauma facility). Shortly after our three stab victims arrive, a code blue goes out over the intercom. The physician covering the wards, Dr. P., is currently in the ED, and Dr. S. is not sure if she's even ACLS certified. Dr. S. and his scribe take off after her with the code box, and I am tasked with getting vitals from the patients. They all appear to be in discomfort, but one looks very pale and is shaking (effects of epinephrine). Dr. S. and his now disheveled looking scribe (CPR will do that to you) return, and the patients are transferred.


So, shadowing is important, an unwritten requirement of medical school. But how do you go about it? I was lucky; I got an internship through the university that handled the initial contact. For those less fortunate, I would suggest asking around the hospital if you volunteer at one. Academic medical centers are probably the best choice because they will be used to having medical students around. Ask your friends too. I came from a completely non-medical family, so I was at a bit of a disadvantage. Many of my friends had physician parents or grandparents, so they became a great source of knowledge. There are lots of guides pertaining to shadowing though, so just search SDN or Google for more in depth advice. You don't have to rack up hours and hours of shadowing, but spend one or two full shifts per specialty. It helps to get some variety as well, but even one experience is better than none. Don't forget to have fun, but make sure you reflect on your experiences too. If you really can't see yourself living that life, it might be time to switch paths. That's what shadowing is for. It wipes away some of the glamour, exposing the realism of clinical practice. It disenchants, leaving only the most dedicated behind to finish the journey to medical school.

Sunday, July 15, 2012

Know The Difference: Heart Attack vs Cardiac Arrest

Welcome to the second installment of "Know the Difference," a series which seeks to clear up common medical misnomers. This week, we're tackling a one of the most prominent naming errors on television (and by extension, the public). The scene is a hospital room, with the patient lying in the bed looking quite unhappy and ill. In walk our doctors, who bear an uncanny resemblance to team featured on House. They chat with the patient briefly, exchange some comical banter with each other, and then the patient takes a turn for the worse. The camera pans up to the cardiac monitor, which shows a complete asystole (flat line). Everyone springs dramatically into action, but one of the doctors commits a medical student faux paus. "She's having a heart attack!" he exclaims, sending a brief jolt of pain to the frontal lobes of the clinical staff watching at home.

So what happened? Basically the hotshot doctor was confusing two conditions, heart attack and cardiac arrest. And since they are treated very differently, it is kind of a big deal to get it right. So how do you tell one from the other?

A cardiac arrest (CA) occurs when the heart is no longer pumping blood. This is determined clinically by checking for a pulse. If it is absent, congratulations; you now have a genuine emergency on your hands. When the heart stops pumping blood, oxygen and nutrients cannot circulate through the body, and waste begins to build up. Without intervention, CA is fatal in a matter of minutes (predominantly due to the lack of oxygen)(1). CA is treated differently depending on the cause and EKG interpretation. For instance, the most common one seen on TV is asystole:

Asystole. Note no discernible waves. Courtesy of wikipedia.
This is also the most common rhythm seen in Out-of-Hospital arrests(2). Asystole has a number of causes, some reversible some not. Typically, this rhythm is seen after prolonged pulselessness, so the prognosis is grim. The treatment usually involves reversing the underlying condition (toxicity, tamponade, tension pneumo, etc). What it does not involve is electrical shocks. Asystole is not a shockable rhythm. So, while making for very good television, our team of doctors would not be doing any good with the defibrillator in the typical case. Ventricular fibrillation (V-fib or VF) on the other hand, is shockable, even though it may not look like an abnormal rhythm to the untrained eye.
V-fib. Only random waveforms. Also courtesy of wikipedia.
VF is a pulseless rhythm where the heart is contracting randomly, out of sync. 

A heart attack (MI) is also a serious condition, but does not lead to death per se. An MI occurs when blood flow to the heart is reduced, classically causing chest pain (angina) and dyspnea(2). The reduction of blood flow is usually due to a narrowing in one or more of the coronary arteries. Thus, the primary intervention is to open the arteries back up (PCI) or bypass blocked portions (CABG). The main difference between MI and CA is that cardiac arrest is a complication of an MI. If the blood flow is cut off for too long, heart muscle (myocardium) will die. This can lead to arrhythmias or heart failure, which may lead to death. The EKG of a person having a heart attack can vary substantially, but here are some examples of anterior MIs.

Summary
CA: No pulse, heart is not pumping blood. Rapidly fatal. Treatment (resuscitation) depends on the rhythm appearance.
MI: Reduced blood flow to the heart via the coronary arteries. Muscle death may impair normal function of the heart and lead to death.

So the next time you're watching House or Gray's Anatomy (or ER for the slightly older readers), keep an eye on that monitor and get ready to call those actors out on their mistakes!

Sources
1.CPR - adult. PubMed Health. 2011. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001083/. Accessed July 15, 2012.
2. Mader TJ, et al. Out-of-hospital cardiac arrest outcomes stratified by rhythm analysis. Resuscitation (2012), http://dx.doi.org/10.1016/j.resuscitation.2012.03.033.
3. Heart Attack. PubMed Health. 2011. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001246/. Accessed July 15, 2012.

Monday, July 2, 2012

Behavior's Big Bang Theory

First, I'd like to say my alliteration skills are still spot on. Second, this has nothing to do with the popular TV show, The Big Bang Theory. Sorry to disappoint (secretly I hope I tricked you, and you'll decide to stay anyways).

When I spoke about behavior last time, my discussion was mostly limited to defining what it is and how we look at it. To recap, a behavior is anything you do to solve an adaptive problem, and we categorize it functionally rather than structurally. For example, opening a jar of pickles solves the adaptive problem of getting food, but we don't care exactly how you opened it. You could have twisted the lid off like the majority of individuals (let's be honest, the majority of individuals actually gave it to someone else to open), but you also could have hit the jar with a sledgehammer or treated it to some explosives a la Mythbusters. Each of these techniques would have opened the jar, but some work better than others. The twisting method is quick, easy to do, and requires minimal energy. Blowing up the jar is more pleasing to the senses, but it requires access to explosives and time to set them up, generates new adaptive problems (flying shrapnel, angry neighbors, destroyed kitchen, etc), and probably obliterates the pickles in the process. So, the next two logical questions to ask are, "Where does behavior come from?" and "How do we find the right one for the job?"

Now, when we ask for the origins of behavior, we are really asking, "What causes behavior?" There are several answers to this depending on your frame of reference. Physiologically, behavior arises as an emergent property (epiphenomenon if you will) from the behavior of multiple neurons (and their effector organs) working together. I would be more specific if I could, be we actually have not yet identified most behaviors to particular networks of neurons. If you filled a backpack with headphones, the resulting tangled mess would give you a good analogy for the complexity of the brain. Untangling the mess is the job of neuroscientists, neuropsychologists, and basically anyone whose title starts with neuro. Behaviorists such as myself stick to the macroscopic world (but we still find the microscopic interesting), dividing our causes into two categories: proximate and ultimate. A proximate cause is the immediate antecedent to the behavior. For the behavior of answering the phone, the proximate cause is the phone ringing. The ultimate cause is more difficult to explain, but suffice it to say, determines why you behave due to a history of reinforcement. For example, you have to drive from Point A to Point B. You take route #1, but it's rush hour and it takes a long time to get there. After doing this several times, you take route #2. It is still rush hour, but you get from A to B much faster. Now the weekend comes. You take route #1 and get to point B in about the same amount of time as route #2, even though it's the same time of day. Gradually, your response is shaped to taking route #2 during rush hour and route #1 during weekends. The route you take (response) due to rush hour + time of day (cues) is a result of a history of reinforcement. If someone asked you why you took route #2 during rush hour, your response summarizes the ultimate cause (It is faster than route #1). So, the proximate cause explains why you behaved in one way as opposed to another, and the ultimate cause explains how you developed that way of behaving.

The mistake most people make when talking about behavior is dismissing the ultimate cause. When a guy in line at the coffee store yells at the person serving his coffee, you may be tempted to say, "He yelled at the worker because he is a jerk." That explains everything right? Jerks yell at people; it makes sense. Unfortunately, by doing that, you fell into B.F. Skinner's 3rd circle of Hell. Your reasoning is actually circular reasoning; he yelled at the worker because he is a jerk, and the guy is a jerk because he yelled at the worker. The ultimate cause is much less visible, having occurred in the past and over a period time, so it is very easy to miss. Additionally, the ultimate cause may be a product of evolution, further obscuring it. Widespread obesity can be attributed to physiologic mechanisms that evolved to prevent starvation (epitomized in meme form as, "Eat all the things!").

At this point, I've provided a partial explanation for the origin of behavior. Tune in next time for the epic finale.